Elastomeric vehicle vibration damping devices

Abstract

Motor vehicle vibration damping parts based on an ethylene, alpha-olefin, vinyl norbornene elastomeric polymer are manufactured with more efficiency due to vibration damping part compounds having lower viscosity, easier processing than ethylene, alpha-olefins, diene monomer compounds, where the diene monomer is other than vinyl norbornene. Additionally, the engine mounts or other vibration damping parts based on the ethylene, alpha-olefin, vinyl norbornene elastomeric polymer have better heat aging characteristics than natural rubber, when temperature of service exceed 120° C., maintain more constant dynamic characteristics of the mount when running at elevated temperature like 120° C. Finally the engine mounts or other vibration damping parts based on the ethylene, alpha-olefin, vinyl norbornene elastomeric polymer can be manufactured with compound containing less peroxide as curing agent, than ethylene, alpha-olefins, diene monomer compounds, where the diene monomer is other than vinyl norbornene. Those engine mounts or other vibration damping parts based on the ethylene, alpha-olefin, vinyl norbornene elastomeric polymer provide better aging properties so the service life of the parts are greatly extended vs. natural rubber part.

We claim: 
     
       1. A vehicle part comprising an ethylene, α-olefin, vinyl norbornene elastomeric polymer; wherein said elastomeric polymer: a) includes ethylene in the range of from about 40 to about 90 mole %;   b) includes vinyl norbornene in the range of from about 0.2 to about 5.0 mole %;   c) has a branching index in the range of from about 0.1 to about 0.6; and   d) has a Mooney viscosity ML (1+4), 125° C. from about 80 to MST (5+4),200° C. up to 90; wherein a compound including said ethylene, α-olefin, vinyl norbornene elastomeric polymer has:     i) ML 1+100° C. up to about 80;   ii) MH-ML above about 50 daN.m;   iii) cure rate of at least about 15 daN.m/min.;   iv) 100% modulus of up about 3 MPa;   v) compression set 22H/125° C. / 25% deflection up to about 20%;   vi) compression set 22H/150° C./25% deflection up to about 25%;   vii) loss tangent below about 0.2 at +26° C.;   viii) loss tangent below about 0.2 at +80° C.;   ix) loss tangent below about 0.2 at +125° C.;   x) a glass transition temperature of about -40° C. measured by DMTA (Dynamic-mechanical-thermal analyser) machine@1 Hz.   
     
     
       2. The vehicle part of claim 1 wherein said ethylene, α-olefin, vinyl norbornene polymer includes ethylene in the range of from about 50 to about 70 mole percent, and said vinyl norhomeric being present in the range of from about 0.2 to about 3 mole percent, said mole percents based on the total moles of said ethylene, alpha-olefin, vinyl norbornene polymer. 
     
     
       3. The vehicle part of claim 1 wherein said ethylene, alpha-olefin, vinyl norbornene polymer includes ethylene in the range of from about 50 to about 65 mole percent, and vinyl norbornene in the range from about 0.2 to about 2 mole percent, based on the total moles of the elastomeric polymer. 
     
     
       4. The vehicle part of claim 1 wherein said ethylene, alpha-olefin, vinyl norbornene polymer includes ethylene in the range of from about 50 to about 65 mole percent, and vinyl norbornene in the range from about 0.4 to about 1.5 mole percent, based on the total moles of the polymer. 
     
     
       5. The vehicle part of claim 4 wherein said alpha-olefin is propylene. 
     
     
       6. The vehicle part of claim 4 wherein said compound has: a) ML 1+4 100° C. up to about 60;   b) cure rate at least about 20 daN.m/min.;   c) 100% modulus up to about 1.5 MPa; and   d) compression set up to about 22H/125° C./25% deflection up to about 10%.   
     
     
       7. The vehicle part of claim 1 wherein said vehicle part is selected from the group consisting of engine mounts, transmission mounts, chassis/body insulators, and combinations thereof. 
     
     
       8. The vehicle part of claim 1 wherein said vehicle part is an engaging mounts, wherein said engine mount further includes an additional vibration dampening device selected from the group consisting of hydraulic, pneumatic mechanical devices, and combinations thereof. 
     
     
       9. A vehicle engine mount comprising an ethylene, propylene, vinyl norbornene elastomeric polymer wherein; a) said ethylene is present in the said polymer in the range from about 50 to about 65 mole percent, and said vinyl norbornene is present in said polymer in the range from about 0.4 to about 1.5 mole percent said mole percents based on the total moles of said polymer;   b) wherein a compound including said elastomeric polymer has: i) ML 1+4 100° C. up to about 75;   ii) MH-ML above about 50 daN.m;   iii) cure rate of at least about 20 daN.m/min.;   iv) 100% modulus of up about 1.5 MPa;   v) compression set 22H/125° C./25% deflection up to about 5%;   vi) compression set 22H/150° C./25% deflection up to about 10%;   vii) loss tangent below about 0.17 at 23° C. and 15 Hz;   viii) loss tangent below about 0.17 at +80° C. and 15 Hz;   ix) loss tangent below about 0.14 at +125° C. and 15 Hz;   x) a glass transition temperature of about -44° C. measured by DMTA @1 Hz.     
     
     
       10. A vehicle comprising a vehicle body and vibration damping parts; said vibration damping parts including a compound an ethylene, propylene, vinyl norbornene elastomefic polymer, wherein said vibration damping parts are formed from a compound having a Mooney viscosity ML 1+4, 100° C. below about 80, preferably below about 50, said compound having a MH-ML in the range of 40 to 50 daN.m.